This invention relates to an airlift shock absorber having an inflatable air sleeve to adjust the riding height of the vehicle upon which the shock absorber is mounted.
Modern motor vehicles have suspension system, which include shock absorbers to control the relative movements of the vehicle chassis with respect to the vehicle body. These shock absorbers commonly include a housing and a piston assembly. The piston assembly includes a piston and a piston rod extending from the piston. The housing is commonly connected to a vehicle wheel end assembly. The housing is filled with a damping fluid, which is metered across the piston plate to dampen relative movement between the housing and piston assembly. The piston rod includes a portion extending from the top end of the housing, which is connected to the vehicle body through a conventional top mount. A jounce bumper is secured below the top mount to absorb the force of unusually large relative movement between the chassis and body. An airlift shock absorber includes an air sleeve that may be inflated to control the relative positions of the piston assembly and housing, to thereby control the riding height of the vehicle.
In conventional prior art airlift shock absorbers, a pressure retainer is attached and sealed to the piston rod. The damping load transmitted through the piston assembly, any load transmitted through the jounce bumper, and the load generated by the airlift mechanism are all transmitted through the piston rod and into the top mount. This increases noise during normal movements of the suspension system and increases ride harshness due to heavy loading at the top mount.
According to the present invention, damping forces are transferred through the top mount and airlift forces and forces transferred through the jounce bumper are transferred through a flexible force receiving member bonded to the top mount housing. The assembly isolates the damping forces from the airlift and jounce bumper forces, and also provides a simplified design, thereby reducing component cost and assembly labor. The airlift mechanism includes a rigid pressure retainer which is an integral part of the top mount, being connected to the top mount by a flexible force receiving member which allows the pressure retainer to flex relative to the top mount. This rigid pressure retainer is bonded to the top mount housing through the flexible force receiving member because the pressure retainer is inserted into the mold during the molding process in which the flexible force receiving member is formed and bonded to the top mount housing. The flexible force receiving member provides the seal and the flexibility required between the two components. Damping loads are transmitted through the conventional top mount in the normal manner. Airlift load and load generated by impacts on the jounce bumper are reacted to the vehicle body through a resilient member for added isolation. Accordingly, dual load paths are provided which are independent of, and isolated from, one another. Noise and ride harshness are thereby reduced.